The present invention relates generally to lighting control systems. More particularly, the present invention relates to a lighting control method wherein a light fixture identifies output signals from an associated occupancy sensor network and regulates a lighting state based on determined occupancy in a defined area.
Due to the improvements in LED lighting technology, the potential energy savings and legislation by the states and the U.S. Department of Energy, the lighting industry is increasingly moving toward controllable lighting. Controllable lighting systems typically employ wired connections to support communication between the controllers and the devices being controlled (e.g., DALI, 0-10V). This poses a cost problem for retrofits where the control wires are not already in place. While the cost is relatively less, the same problem exists in new construction where the wires must be procured and routed.
Alternative lighting control techniques include the use of power line control or wireless control. Power line control is susceptible to influence from noise and, in some implementations, requires bulky controls.
Wireless lighting controls have been employed on a limited basis, and typically use bi-directional messaging on relatively expensive platforms. The protocols include error correction and support multiple types of messages. Many of these conventional systems operate on a mesh network. While these systems are powerful in their ability to transmit a significant amount of data, the devices employed are expensive; the software development is often significant; and system commissioning and troubleshooting are complex.
Transmitting large amounts of data requires the use of unlicensed wireless bands that allow continuous data transmission (2.4 GHz). However, continuous data wireless bands are limited in their output power compared to unlicensed wireless bands targeted for spurious data transmission with very low duty cycle (400 MHz).
Further, many of the available wireless technologies are problematic in that they require significant research and development to implement them, they require skills typically unfamiliar to individuals installing lighting systems (e.g., network technology), and/or they are often difficult to troubleshoot (e.g., determine which device is failing).
It would therefore be desirable to provide a lighting control system that is fast and easy to commission, easy to troubleshoot, and relatively inexpensive.
It would further be desirable to provide a robust lighting control system that is substantially immune to noise.
It would further be desirable that the system is configured to embody a failsafe, wherein for example in fault conditions, the lights default to a full bright condition.